[carlstronomy (Carl)]

The best way to heat a mirror or corrector plate is always direct contact. This is why Kendrick make the heater pads to stick onto the back of the mirror. Heating the tube will not work as the primary mirror does not make contact with the tube wall, doing this would possibly create more of a heat haze in the tube.

I have heard of people wrapping a strip heater around the actual mirror, unsure how effective it would be. The proper pad would definitely be the best if you have major condensation issues, nothing wrecks viewing and imaging more than dew.